SiGe-based electronics have a promising prospect in the field of space exploration due to the controllable bandgap of SiGe alloys and high compatibility with Si technology. However, they may be susceptible to the influence of energetic particles in space radiation environments. In order to explain the potential displacement damage in SiGe-based electronics, Monte Carlo simulations are conducted to investigate the displacement damage in SiGe alloys and SiGe/Si heterostructures induced by 1–1000 MeV protons. The displacement damage in SiGe alloys is studied by the energy spectra and types of proton-induced primary knock-on atoms (PKAs) and the related damage energy distribution, while the displacement damage in SiGe/Si heterostructures is studied by the damage energy distribution caused by forward- and reverse-incident protons. Low-energy protons (1–100 MeV) primarily generate Si PKAs and Ge PKAs in SiGe alloys through Coulomb scattering and elastic collisions, and the corresponding damage energy distribution exhibits a distinct Bragg peak at the end of the proton range. Meanwhile, high-energy protons (300–1000 MeV) cause significant inelastic collisions in SiGe alloys, leading to a series of other PKA types, with the associated damage energy distribution predominantly located in the front of the proton range. In addition, the damage energy in SiGe/Si heterostructures generally decreases as the proton energy increases, and compared with the forward-incident protons, the reverse-incident protons (10 MeV and 100 MeV) cause greater damage energy on the side of Si substrate at the interface, and result in more noticeable fluctuations in damage energy on both sides of the interface, probably leading to severe displacement damage. Besides, Ge content can affect the PKA type, damage energy distribution, and nonionizing energy loss. As for high-energy protons, high Ge content may lead to a great nonionizing energy loss in SiGe alloys, whereas the Ge content has an insignificant effect on the total damage energy of small-size SiGe/Si heterostructures. In summary, this work indicates that the proton-induced displacement damage in SiGe alloys and SiGe/Si heterostructures is greatly dependent on the proton energy, and low-energy protons are prone to generating massive self-recoil atoms, inducing significant displacement damage in small-size SiGe/Si heterostructures, which will provide theoretical basis and reference for studying displacement damage effect and developing radiation hardening techniques of SiGe-based electronics.